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Banding process

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The banding process of electrical motor rotors is a key operation to guarantee an excellent quality on the final product so it is important to do it carefully. That is why you have to use the best technologies and products available on the market.
The leading banding tape manufacturers like VON ROLL ®, ISOVOLTA ® and DUPOND ® identify three important variables that you have to control and monitor to obtain an excellent bandaging:

Hereunder you can find an in-depth analysis of the above-mentioned variable:

Tape tension

The banding tape has to be applied with a high mechanical tension. VON ROLL ®, like other manufacturers, depending on the tape type, recommends a tape tensioning force ranging from 80 kg up to 150 kg per each 10 mm of tape width.

It is fundamental to maintain the tape tension inside this range because different values could damage the integrity of the insulation beneath during the application phase and/or during the curing cycle.

To better meet this requirement RIMAC integrated in its banding machines a very efficient and highly precise automatic control system based on load cell technology.

This solution generates a precise and continuous tape tension control that remains constant during the entire banding process according to the initial value set by the operator.
Even during a stop rotation phase this system allows the tape to maintain the correct tension.

Temperature control

The banding tape can be applied either at room temperature or at hot temperature. The best application, like ISOVOLTA ®, VON ROLL ® and DUPOND ® recommend, is the hot one because high temperatures generate a softening phenomenon of the resin composing the tape, allowing the glass fibers to penetrate in depth between the different tape layers.

The temperature during the banding process should be maintained between 80°C and 100°C. This generates a 60-70% retained tension instead of only 10 -15% retained tension for banding process at room temperature (VON ROLL ® data).

RIMAC system to control the temperature of tape and banding area (tape infra-red preheating device) is based on the physical principle of heat exchange by irradiation thanks to one or more infrared lamps being suitably positioned. This system allows to remain in the temperature range indicated by tape manufacturers.

RIMAC uses a double temperature control system to assure the highest possible precision:

  • Infrared lamps temperature control performed by thermocouples

  • Tape temperature control by means of pyrometers

This multi-control system is able to guarantee high performances meeting the prescriptions given by international tape manufacturers like ISOVOLTA ®, VON ROLL ®, DUPOND ®, etc. This systems also has a special eye on energy saving and consequently on the reduction of production costs.

Banding speed

In general, the leading tape manufacturers suggest a tape application speed ranging from 7 m/min up to 20 m/min, depending on the specific tape features.

RIMAC banding machines are all equipped with a variable-speed system and with a speed and positioning control system (Encoder). This technology is able to guarantee the highest precision to maintain the initial speed value set by the operator.

To simplify this initial parametrization phase, RIMAC developed a software interface where the operator has to enter only tape speed and rotor diameter of the piece being manufactured. This means that the software automatically sets the rotation speed of the rotor and the speed rotation of the tape.

To obtain the highest repeatability rate for banding operations, by maintaining the standard performances being the target, RIMAC developed a software to bring the banding operations to an automatic level. In this configuration the operator only has to enter the rotor diameter and to activate the chosen working cycle.
At this point the machine auto-sets itself and it’s ready to start the working cycle.
All RIMAC banding machines are compatible with the main tapes on the market. In particular, they can work with tape width between 3mm and 30 mm and with tape reels width up to 280 mm.

Generally speaking, RIMAC banding machines are innovative, flexible and highly precise machines, able to guarantee the highest working standards. From the smallest rotors of brushless motors with permanent magnets, to medium voltage AC/DC motor banding, up to big turbogenerator rotors, RIMAC banding machines cover all the possible rotor dimensions.

RIMAC is one of the leading companies in this market and it is continuously focusing on research & development and on the formulation of customized solutions to meet all the costumers' requirements.